1. Technical Field
The present invention relates to an illuminator and a projector.
2. Related Art
JP-A-2012-137744, for example, discloses an illuminator which is used in a projector and in which a retardation film through which light from a solid-state light source unit including a plurality of semiconductor lasers passes is rotated to change the ratio between an S-polarized component reflected off a dichroic mirror and incident on a fluorescence emitting plate and a P-polarized component passing through the dichroic mirror and incident on the reflection plate.
In general, to increase the brightness of an image displayed by a projector, the amount of light outputted from an illuminator may be simply increased. As an example for achieving a bright image, USP Application Publication No. 2004/0252744 discloses an illuminator that combines light beams emitted from two laser arrays with each other to increase the amount of light. The illuminator uses a polarizing beam splitter or a plurality of stripe mirrors as a light beam flux combining element that combines light beam fluxes with one another. In the case where a polarizing beam splitter is used as the light beam flux combining element, the polarizing beam splitter transmits P-polarized light emitted from one of the laser arrays and reflects S-polarized light emitted from the other laser array to combine the two light beam fluxes with each other.
On the other hand, in the case where a plurality of stripe mirrors are used as the light beam flux combining element, the plurality of stripe mirrors cause the light emitted from one of the laser arrays to pass through the spaces between the mirrors and further cause the light emitted from the other laser array to be reflected off the mirrors to combine the two light fluxes with each other.
To increase the amount of light in the illuminator in JP-A-2012-137744, it is conceivable to combine the illuminator with the polarizing beam splitter disclosed in USP Application Publication No. 2004/0252744. In a case where the two laser arrays emit the P-polarized and S-polarized light beams of the same amount, however, the ratio between the S-polarized light incident on the fluorescence emitting plate and the P-polarized light incident on the reflection plate cannot be changed even by rotating the retardation film.
It is further conceivable to combine the illuminator in JP-A-2012-137744 with the plurality of stripe mirrors disclosed in USP Application Publication No. 2004/0252744. In a case where the distance between the light beams emitted from the plurality of semiconductor lasers is smaller than the diameter of the light beams, the light beams are blocked by the stripe mirrors, resulting in optical loss. The pitch at which the semiconductor lasers are arranged cannot therefore be reduced, and it is therefore difficult to reduce the size of the illuminator. Further, it is necessary to align each of the stripe mirrors with the semiconductor laser corresponding to the stripe mirror, and the alignment task is cumbersome.